Mapping New Directions in Paired-Agent Imaging

Kenneth Tichauer, Armour College of Engineering Assistant Professor and Developer of the ADEPT Cancer Imager

The future of tailored cancer drug therapy lies within the lima bean-shaped image on a computer screen in Illinois Tech’s Medical Imaging Research Center. The image depicts a whole porcine lymph node illuminated by bright red and green points of injected fluorescent dyes and is the first produced with the ADEPT Cancer Imager. The innovative device produces a 3-D high-resolution molecular map of a piece of tissue such as a lymph node indicating microscopic areas where cancer has spread, and at a far more minute level than existing imagers.

“Lymph nodes drain the primary tumor, which is the reason physicians look for cancer that is spread there. The treatment for metastatic disease is very aggressive; you would not want to give that treatment to somebody who did not need it. Physicians need some way of identifying who should be given the aggressive treatment,” says Assistant Professor of Biomedical Engineering Kenneth Tichauer, developer of the ADEPT (Agent-Dependent Early Photon Tomography System) Cancer Imager. He notes that current studies indicate that patients who have microscopic levels of metastatic disease and who would benefit from a more aggressive therapy are being missed 30 to 60 percent of the time. “Patients are then coming back later with a more advanced disease than before they started cancer therapy. Our idea is to make the detection of that metastatic disease more sensitive than what is now being done.”

Tichauer’s research group (including co-principal investigators Jovan Brankov (M.S. EE ’99, Ph.D. ’02), a systems development expert and associate professor of biomedical engineering/electrical and computer engineering, and Rajendra Mehta, a biologist with IIT Research Institute) is currently working with pig lymph nodes that have been injected with human cells or cells harvested from human cancer grown in an immune-compromised mouse. These nodes are then injected with biologically active fluorescent substances (fluorophores, which display as red and green) that chemically interact with the tissue, seeking out proteins that are over-expressed by breast cancer. The node is then suspended in the imager and photons, or light particles, pass through the tissue, resulting in a cross-sectional image displaying a “map” of where the red and green dyes, also known as paired agents, have traveled. The tissue specimen can be rotated 360 degrees in the ADEPT chamber so that a 3-D reconstruction can be produced. A larger amount of the protein-seeking dye indicates the presence of cancer while an equivalent proportion of dye distribution would indicate no presence of cancer.

“We’ve become leading experts in paired-agent imaging, which allows for quantitative mapping of the cancer molecules,” says Tichauer, adding that in a clinical setting, the images would reveal the exact area where cancer cells lie within minutes, thereby allowing medical experts to accurately process the tissue specimen and decide upon the course of treatment.